Telephone system



March 12, 1935. 5. H. PETERSON TELEPHONE SYSTEM Filed Fep. 18, 1955'INVENTOR v G H PETERSON A TTORNEV Patented Mar. 12, 1935 UNITED STATES 1F I E reclai s. (o1. 179-51 This invention relates to telephone systemsand more particularly touniversal cor-d circuits for interconnectingtelephone lines of like or unlike character. I

An object of the invention is to interconnect lines of like or unlikecharacter and toprovide supervision for said connections,

A further object is to prevent fortuitous operation of the signals ofsaid cord circuits.

A feature of the present invention whereby the foregoing objects areattained resides in interlocking relay circuits whereby-a plurality ofrelays will release simultaneously and circuit conditions conducive tofalse signal operation will be avoided.

Theinvention will be understood from the following description togetherwith the accompanying drawing in which one embodiment-of myinvention isshown as applied to a universal cord circuit similar to that of 'Fig. 1of the-application of H. W. Ulrich, Patent No. 1,904,017, issued April18, 1933 which shows an arrangement for interconnecting magneto andcommon battery telephone lines. a I

V Circuit-description The present circuit is substantially'similar tothat shown'in the above mentioned patent. A and B are two subscribers"common battery telephone stations and C and Dam two subscribers magnetotelephone stations connected by tele-' phone lines with the centraloffice wherein the lines'are terminated at a switchboard in multiplejacks. A line lamp is associated with one of-the jacks connected to eachcommon battery line and a line drop is associated with one of the jacksconnected to each magnetoline.

The universal cord circuit E is one of several situated at an operatorsposition at a switchboard, any of which may beconnected to the operatorstelephone circuit F by the operation of the individual cord circuittalk'key, as for example key 106 in cord circuit We will assume thatjack and associated line lamp 101, jack 102 andassociated line drop 103,jack 104 and jack 105 are located at the switchboard operators positionwith which cord circuitE and telephone circuit F are associated and thatthe other jacks and line signals are located elsewhere in theswitchboard. I

Cord'circuit E-is provided'with answering and calling plug terminals 107and 108, respectively. Answering and calling sleeve relays 109 and 110operate in response to connections to common battery lines and connecttalking battery I through the answering and calling supervisory relays111 and 112, respectively, to the answering and the callingend of thecord talking conductors. Relays 111 and 112 control the answering andcalling cord supervisory lamps 113 and 114, respec tively. i g V vCondensers 11 5 and 116 are inserted in the tip and: ring cord talkingconductors, respectively, in order to prevent the passage of directcurrent, but to allow variable talking current to be freely transmitted.

Cord drop 117 is designed to operate on alter nating current from asubscribers magneto generator and is normally bridged from the tipconductor of the answering cord to the ring conduc: tor of thercallingcord. Relay109 in operating, with relay 110 unoperated, disconnects drop117 from the tip of the answering cord and connects it between tip andring conductors of the calling cord, while relay l10in operating withrelay 109 unoperated, transfers the connection of drop 117 to the tipand ring conductors of the answering cord. With relays 109 and 110 bothoperated, however, drop 117 is entirely disconnected from both ends ofthecord. v f My present invention is directed to the meansfor-preventing false operation of the drop 117 upon a disconnection ofthecord E from common battery telephone lines. Upon a connection beetween common battery lines Aand B, sleeve relays 109 and 1100f cordcircuit E will both be operated as long as their respective connectingplugs are-inserted in jacks of the telephone lines. Upon disconnection,if calling cord plug 108 were re moved from its associated jackbeforeanswering cord plug 107, and relay 110 were to release, drop 117would be bridged across the talking conduc tors of the ,calling cord.This would create a charging path for condensers 115 and 116 frombattery through thelower winding of answering supervisory relay 111,front contact of answering sleeve relay 109, condenser 116, back contactof calling sleeve relay 110, normalcontactof talk key 106, drop 117,front auxiliary contact of relay 109, back contact of relay 1'10,condenser 115, front contact of relay 109, upper Winding of relay 111 toground. Drop 117 is liable to operateon the surge of charging currentwhich would result. In accordance with the present invention, theanswering and calling sleeve relays 109 and 110 have interlockingholding circuits whereby both relays will beheld operated uponconnection between co-mmon battery lines until both connecting p u -1108 a en-re ar ed ir m t jacks of the connected lines. The holdingcircuit comprises conductors 135 connected to the sleeve conductor ofthe answering cord, uppermost contacts of answering sleeve relay 109,conductor 136, normal contacts of talk key 106, conductor 137, uppermostcontacts of calling sleeve relay 110, conductor 138 to the sleeveconductor of the calling cord. Upon both relays 109 and 110 beingoperated they are both held on circuits connected to ground on thesleeve of either the calling or called line. Upon removal of the secondplug from its associated line jack both relays 109 and 110 will releasesimultaneously thereby avoiding the charging condition.

The operators telephone circuit F contains a transmitter 118 andreceiver 119 and is provided with an arrangement for obtaining a clickbusy test upon both common battery and magneto lines.

Operation The operation of the circuit is as follows: 7

On a call from common battery station A the subscriber removes thereceiver from the switchhook thereby closing the circuit from battery125, through line lamp 101, contacts of jack 110, contacts of jack 126,through subscribers set A, contacts of jack 126, contacts of jack toground 127, thereby causingline lamp 101 to light as a signal to theoperator. The operator inserts the plug 107 of the answering cord injack 100 thereby opening the normally closed contact of the jack andextinguishing line lamp 101, and connecting ground to the sleeve at thenormally open contact 128. Relay 109 operates and cord supervisory lamp113 may-light momentarily on current from battery in the cord circuit toground on the jack sleeve. The operation of relay 109 connects groundand battery to the tip and ring of the cord through the winding of relay111 operating this relay which opens the circuit for lamp 113. Relay 109also disconnects the winding of drop 117 from the tip conductor of theanswering cord and connects it fromthe tip to the ringof the callingcord.

The operator answers the callwith the talk key in the operated position.Now having a talking connection with the party at station A, theoperator ascertains the number of the line desired by him. Assuming thatthe call is for common'battery station B, she thereupon performs a busytest in the usual manner and finding the line idle she inserts plug 108in jack 104 thereby disconnecting line lamp 129 and the multiple jackfrom the talking conductors by opening the normally closed jack contactand connects ground to the jack sleeve at the normally open contact ofthe jack. Relay 110 operates and lamp 114 lights from battery in thecord circuit to ground on the sleeve of jack 104. The operation of relay110 connects ground and battery through the winding of relay 112 to thetip and ring of the calling cord and opens the circuit for drop 117,disconnecting it from the cord.

The operator releases talk key 106 and operates ringing key 133 applyingringing current to the line and ringing the called subscriber. After asuitable ringing interval, she releases key 133. When the calledsubscriber answers, relay 112 operates extinguishing lamp 114.

At the completion of the conversation, subscriber B hangs up causingrelay 112 to release thereby lighting lamp 114. When the subscriber atstation A hangs up, relay 111 releases lighting lamp 113. I

The operator thereupon pulls down the calling cord terminating in plug108. Calling sleeve relay 110 remains operated, however, a lockingcircuit being maintained for it from battery through its own winding andthe previously described holding circuit to ground on the sleeve of theanswering cord. If answering supervisory lamp 113 glows steadily,indicating a disconnect signal from the calling line, the operator pullsdown the answering cord thereby removing. ground from the sleeveconductor and simultaneously releasing sleeve relays 109 and 110. Ifanswering supervisory lamp 113 flashing, however, indicating that thecalling subscriber is moving his switchhook up and down to signify arecall, the operator presses her talk key 106 connecting her telephoneset to the cord, opening the holding circuit for calling sleeve relay110 and opening the circuit through drop 117. This releases relay 110,but false operation of drop 117 cannot occur since the circuit throughthe drop is also opened at the talk key. The operator thereuponascertains the number of the second line the calling subscriber desiresand. proceeds as with an original call.

Assuming now that the call from common battery station A is for magnetostation D, the operator makes a busy test on jack and finding the lineidle, inserts plug 108 in jack 105 thereby disconnecting the multiplejack and line drop 130 from the talking conductors. On this connectionthe relay does not operate and lamp 114 does not light. Drop 117 remainsin this case bridged across the tip and ring of the calling cord. Theoperator now rings in the usual manner and then listens until the calledsubscriber answers whereupon she releases talk key 106. I

When the subscriber at station B disconnects, he operates his handgenerator 134 thereby applying alternating current to the line tooperate drop 117 in the cord circuit. When the subscriber at station Adisconnects, relay 111 releases and the cord supervisory lamp 113 lightsas before. The operator after challenging on the call pulls down bothplugs and manually restores drop 117.

On a call from magneto station C, the subscriber operates his magnetogenerator 131 which sends alternating current over the line throughcontacts of jacks 132 and 102 and through the winding of line drop 103causing it to operate, giving a signal to the operator. The rest of theoperation will be readily understood from the foregoing descriptiontaking into account the manner of operation of each end of the cord onmagneto and common battery connections.

While the present invention is disclosed as embodied in certain specificarrangements, applicant does not wish to be limited by-such disclosure,but desires to cover broadly all arrangements that come within thespirit and scope of the appended claims.

What is claimed is:

1. In a signaling system, a signaling circuit, a signal receiving devicenormally connected to said circuit, asource of electric current, a pairof relays cooperatively acting when operated to disconnect said devicefrom said circuit and individually acting when operated to connect saidcurrent source to said circuit, and locking means effective when bothrelays are operated to prevent one relay from releasing before theother.

2. Ina signaling system, a signaling circuit, a signal receiving devicenormally connected tosaid circuit, a source of electric current, a pairof relays cooperatively acting when operated to disconnect said devicefrom said circuit and individually acting when operated to connect saidcurrent source to said circuit, and means to precircuit containing thecurrent source to the talking conductors and to jointly disconnect saiddevice from said conductors, said means being arranged to preventreconnection of said device to the talking conductors beforedisconnection 'of the current source therefrom. i

4. In a telephone system, a pair of 'talling'conductors, a signalreceiving device normally connected'across said conductors, a source ofelectric current, a pair of relays cooperatively acting when operated todisconnect said device from said conductors and individually acting whenoperated to connect said current source across 'said conductors, andlocking means effective when both relays are operated to prevent onerelay from releasing before the other.

5. In a telephone system, a pair of talking conductors, anelectromagnetic signal, a circuit therefor normally bridged across saidconductors, a circuit containing a source of electric current, a pair ofrelays cooperatively acting when operated to disconnect said device fromsaid circuit and individually acting when operated to connect saidcurrent source to said circuit, and a common holding circuit for bothsaid relays to prevent other than simultaneous release of the relayswhen both have been operated.

6. In a telephone system comprising lines of two different characters, auniversal cord circuit for interconnecting any two of said lines,answering and calling connecting terminals for said cord circuit, tipand ring conductors connecting said terminals, an electromagneticsignal, a circuit therefor normally bridged across said conductors, asource of electric current, relays individual to each end of said cordcircuit to bridge said current source across their respective ends whenthe associated connecting terminal is connected toa line of a firstcharacter, both of said relays cooperating to disconnect saidelectromagnetic signal circuit and means to prevent other thansimultaneous release of said relays when both have been operated.

'7. In a telephone system, lines of two different characters, auniversal cord circuit for interconnecting any two of said lines,answering and calljing connecting terminals for said circuit, tip andring talking conductors connecting said terminals,

. sleeve relays operating to connect a source of potential between thetip and ring conductors of their respective ends of the cord when theassociated terminal is connected to a first type of line, said relayscooperating to disconnect said signal controlling electromagnet, andmeans for locking both the sleeve relays operated in the same holdingcircuit.

8. In a telephone system comp-rising lines of a first and a secondcharacter, impulse sending means associated with lines of the secondcharacter, a universal cord circuit for interconnecting any two of thelines, answering and calling connecting terminals for said cord circuit,tip and ring conductors connecting said terminals, in-

ductive means included in each of said conductors, a supervisory signalfor each'of the cords, an individual supervisoryrelay: for controllingeach signal normally disconnected from said conductors, a current sourcein series with said relay, a signalcontrolling winding responsive tosaid impulse sending means normally connected between the tip conductorof one end .of the cord and the ring conductor of the other end, meansresponsive to the connection of either terminal to a line of the firstcharacter to connect its associated-relayto that end of the cordcircuitand to disconnect and transfer the impulse responsive winding fromthatend to the opposite end and responsive to the connection of bothterminals to lines of the first character to'entirely disconnect saidwinding, and means-to prevent reconnection of the impulseresponsivewinding before both said supervisory relays are disconnected.

9. In a telephone system comprising two types of lines, a universal cordcircuit for interconnecting any two of said lines, answering and callingconnecting terminals for said cord circuit, tip and ring conductorsconnecting said terminals, inductive means included in each of saidconductors, a supervisory signal for each end of said cord, anindividual supervisory relay for controlling each signal normallydisconnected from said tip and ring conductors, a current source inseries with each of said relays, a signal controlling winding normallyconnected between the tip conductor of one end of the cord and the ringconductor of the other end, a switching relay for each end of the cordresponsive to the connection of its respective terminal to one type ofline to connect the supervisory relay at that end of the cord across itstip and ring conductors and to transfer the connection of said signalcontrolling winding, to the opposite end, both of said switching relayscooperating to disconnect said signal controlling winding responsive tothe connection of both terminals to said type of line, and means toprevent other than simultaneous release of said switching relays whenboth are operated.

10. In a telephone system comprising magneto and common battery lines, auniversal cord circuit for interconnecting any two of said lines,answering and calling connecting terminals for said cord circuit, tipand ring conductors connecting said terminals, inductive means includedin each of said conductors, a supervisory signal for each end of saidcord, an individual supervisory relay for controlling each signalnormally disconnected from said tip and ring conductors, a currentsource in series with each of said relays, a signal controlling windingnormally connected between the tip conductor of one end of the cord andthe ring conductor of the other end, a switching relay for each end ofthe cord responsive to the connection of its respective terminal to a.common battery line to connect the supervisory relay at that end of thecord acrossthe tip and ring conductors and to transfer the connection ofsaid signal controlling winding to the opposite end, both of saidswitching relays cooperating to disconnect said signal controllingwinding responsive to the connection of both terminals to common batterylines, and means to prevent other than simultaneous release of saidswitching relays when both are operated.

11. In a telephone system comprising two types of lines, a universalcord circuit for incircuit, tip and ring conductors connecting'saidterminals, inductive means included in each of said conductors, asupervisory signal for each end of said cord, an individual supervisoryrelay for controlling each signal normally disconnected from said tipand ring conductors, a current source in series with each of saidrelays, a third supervisory signal, a controlling winding therefornormally connected between the tip conductor of one end of the cord andthe ring conductor of the other end, a switching relay for each end ofthe cord responsive to the connection of its respective terminal to onetype of line to connect the supervisory relay at that end of the cordacross its tip and ring conductors to transfer the connection of saidthird signal controlling winding to the opposite end, both saidswitching relays cooperating to disconnect said third signal controllingwinding responsive to the connection of both terminals to said type ofline, and means to prevent other than simultaneous release of saidswitching relays when both are operated.

12. In a telephone system, common battery and magneto telephone lines, acircuit adapted to be included in a connection between both types oflines, a current responsive device normally connected to said circuit, adirect current source normally disconnected from said circuit, and dualmeans responsive to connection of said circuit to a pair of commonbattery lines to individually connect said source to the circuit and tojointly disconnect said device therefrom, said means being arranged toprevent reconnection of said device to the circuit until said source isdisconnected therefrom.

GEORGE H. PETERSON.

